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Re: [TowerTalk] Fwd: Grounding of tower

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Fwd: Grounding of tower
From: Jim Lux <jimlux@earthlink.net>
Date: Fri, 10 May 2013 12:38:08 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
On 5/10/13 9:15 AM, Jim Brown wrote:
On 5/10/2013 8:58 AM, George Dubovsky wrote:
In the case of a radial system on or just below the surface of the earth,
one or many ground rods connected anywhere to the rf ground system should
not hurt,

Please remove the phrase "RF ground system" from your vocabulary -- it
is a false concept, and leads to confusion.

Rudy Severns, N6LF, has done a lot of work studying radial systems for
verticals, especially for the lower bands.  Rudy has shown that an earth
connection can significantly degrade the performance of an elevated
radial system. I suspect he might agree that adding an earth connection
to the feedpoint of a dense on-ground radial system would not hurt, and
radials connected a grounded tower certainly have that condition . Earth
connections elsewhere in the radial system are a bad idea, because they
disturb (in a bad way) the current distribution along the radial. Rudy's
published work does a great job of explaining why.



This was also an observation when they were validating NEC3/NEC4. They modeled worse performance with a set of radials plus a ground rod than just the radials alone. They were kind of surprised, so they went out and built a test and verified that it is real.

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